This article summarizes the common examples of operating skills in Python strings. Share to you for your reference, as follows:
Reverse a string
>>> S = 'abcdefghijklmnop'
>>> S[::-1]
'ponmlkjihgfedcba'
This usage is called three-limit slices
In addition, the object slice can also be used, e.g.
>>> 'spam'[slice(None, None, -1)]
>>>
Conversion between unicode character code (single-character strings)
>>> ord('s') # ord -> ordinal
115
>>> chr(115) # chr -> char?
's'
Binary Coded Decimal
>>> B = '1101'
>>> I = 0
>>> while B != '':
... I = I * 2 + (ord(B[0]) - ord('0'))
... B = B[1:]
...
>>> I
13
Binary to decimal calculation here is that we have become accustomed to the calculation methods are not the same, we are generally accustomed to every binary multiplied by the weight and then summed.
The calculation here is actually similar with left shift, calculate the direction from left to right.
(1)2 = 1
(11)2 = (1)2 << 1 + 1
(110)2 = (11)2 << 1 + 0
(1101)2 = (110)2 << 1 + 1
Of course, there's an easier way
>>> int('1101', 2)
13
>>> bin(13)
'0b1101'
Add a break character for each character
>>> S = 'spammy'
>>> L = list(S)
>>> L
['s', 'p', 'a', 'm', 'm', 'y']
>>> L[3] = 'x'
>>> L[4] = 'x'
>>> L
['s', 'p', 'a', 'x', 'x', 'y']
>>> S = '-'.join(L)
>>> S
's-p-a-x-x-y'
>>>
More concise version
>>> 'SPAM'.join(['eggs', 'sausage', 'ham', 'toast'])
'eggsSPAMsausageSPAMhamSPAMtoast'
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